Fishery trophic linkages in the Chesapeake Bay ecosystem: A stable isotope approach (Maryland, Virginia)

Modern fishery management calls for multi-species models and approaches. In order to develop these approaches, a good understanding of trophic linkages under varying conditions is needed. This study serves to determine the validity of applying stable isotope analysis (SIA) to the Chesapeake Bay as well as to identify trophic linkages among fished stocks via carbon and nitrogen SIA. Samples represent important finfish, bivalve, and crab populations in oligohaline (Head of the Bay) and mesohaline regions (Choptank and Tangier Sound) of the Chesapeake Bay. Results suggest that SIA is a valid tool for use in the Chesapeake Bay. δ15N is a good indicator of trophic position, especially at low and mid trophic positions where migration effects play a relatively minor role in observed δ 15N values. δ13C measurements serve to implicate sources of primary production for consumers. An ANCOVA performed on δ 13C measurements with δ15N measurements as the covariate reveals two food webs. One is comprised of the Head of the Bay and Choptank food webs. The Tangier Sound food web stands alone. (Abstract shortened by UMI.)...